1. Field of the Invention
The present invention relates to an electrical conduction mechanism, and relates to, for example, an electrical conduction mechanism suitable to conduct electricity to a weld bit constituting a member of a sheet-metal puller which is advantageous for pulling out a dent on a sheet-metal face during sheet-metal work.
2. Description of Related Art
As a sheet-metal puller which is advantageous for pulling out a dent on a sheet-metal face during sheet-metal work, a sheet-metal puller shown in FIGS. 12 to 14 has been suggested by the inventor of the present application.
A conventional sheet-metal puller 205 shown in FIGS. 12 to 14 is made available with a clamping means 210 of a power source cord 215 attached to a cord connection portion 221B continuously connected to a handle 221 of the sheet-metal puller and with the other end of the power source cord connected to a welder 7, and is capable of efficiently performing within a short time a sequence of sheet-metal work steps of applying current to a bit 225 which is disposed in a distal end portion of a shaft 222 configuring the sheet-metal puller and which is weldable on a sheet-metal face, welding a distal end of the bit on a sheet-metal repair face to pull up a dent on the sheet-metal repair face, and further releasing welding of the bit after pulling up the dent. However, since longer power source cord 215 gains more weight, and electrical conduction is performed by attaching the clamping means 210 of the power source cord to the cord connection portion 221B continuously connected to the handle 221, the following improvements (1), (2), and (3) have been, for example, required. More specifically, the following problems have been pointed out.                (1) Though the position of the center of gravity of the sheet-metal puller is determined on the assumption that it is used in a vertical position, the automotive sheet-metal work often involves repair of an automotive side face, and accordingly the sheet-metal puller is often used in a lateral position as a matter of course (see FIG. 12). However, the cord connection portion 221B of the sheet-metal puller is disposed in an upper portion of the sheet-metal puller, and therefore, when the sheet-metal puller 205 is used in the lateral position, the position of the center of gravity thereof is deviated from that located when the sheet-metal puller is used in the vertical position, due to the weight of the power source cord 215 (if the position of the center of gravity of the sheet-metal puller when it is used in the vertical position is located at P2 in FIG. 12, P2 is deviated downward in FIG. 12, as shown by a broken line in FIG. 12, when the sheet-metal puller is used in the lateral position). Thus, a fulcrum Q2 formed in a first manipulating member 140 of the sheet-metal puller during sheet-metal repair work fluctuates to be unfixed, and even if the sheet-metal work takes a long time, a hand holding the sheet-metal puller gets tired and comes to feel heavy, which results in degradation in workability;        (2) The cord connection portion 221B formed in the handle 221 of the sheet-metal puller 205 and the clamping means 210 of the power source cord are in pivotal contact with each other, and therefore, as the sheet-metal puller 205 is more often used, a peripheral face of the cord connection portion 221B and inner wall faces of clamping bodies 210A, 210B of the clamping means 210, which are in contact with each other, are worn or scratched thereby necessitating replacement of the handle or the clamp means;        (3) Since the clamping means 210 of the power source cord 215 constituting an electrical electrical-conduction unit is exposed outside, dust or the like adheres to the clamping bodies of the clamping means 210, which causes reduction in electrical conduction efficiency;        